import java.io.*;  // For BufferedWriter

public class WolfDeerSimulation {
  
  /* Linked lists for tracking wolves and deer */
  private AgentNode wolves;
  private AgentNode deer;
  
  /** Accessors for wolves and deer */
  public AgentNode getWolves(){return wolves;}
  public AgentNode getDeer(){return deer;}
  
  /* A BufferedWriter for writing to */
  public BufferedWriter output;
  
  /**
   * Constructor to set output to null
   **/
  public WolfDeerSimulation() {
    output = null;
  }
  
  /**
   * Open the input file and set the BufferedWriter to speak to it.
   **/
  public void openFile(String filename){
   // Try to open the file
    try {
      
      // create a writer 
      output = new BufferedWriter(new FileWriter(filename));
      
    } catch (Exception ex) {
      System.out.println("Trouble opening the file " + filename);
      // If any problem, make it null again
      output = null;
    }

  }
  
  public void run()
  {
    World w = new World();
    w.setAutoRepaint(false);
    
    // Start the lists
    wolves = new AgentNode();
    deer = new AgentNode();
    
    // create some deer
    int numDeer = 20;
    for (int i = 0; i < numDeer; i++)
    {
      deer.add(new AgentNode(new Deer(w,this)));
    }
    
    // create some wolves
    int numWolves = 5;
    for (int i = 0; i < numWolves; i++)
    {
      wolves.add(new AgentNode(new Wolf(w,this)));
    }
    
    // declare a wolf and deer
    Wolf currentWolf = null;
    Deer currentDeer = null;
    AgentNode currentNode = null;
    
    // loop for a set number of timesteps (50 here)
    for (int t = 0; t < 50; t++)
    {
      // loop through all the wolves
      currentNode = (AgentNode) wolves.getNext();
      while (currentNode != null)
      {
        currentWolf = (Wolf) currentNode.getAgent();
        currentWolf.act();
        currentNode = (AgentNode) currentNode.getNext();
      }
      
      // loop through all the deer
      currentNode = (AgentNode) deer.getNext();
      while (currentNode != null)
      {
        currentDeer = (Deer) currentNode.getAgent();
        currentDeer.act();
        currentNode = (AgentNode) currentNode.getNext();
      }
     
      // repaint the world to show the movement
      w.repaint();
      
      // Let's figure out where we stand...
      System.out.println(">>> Timestep: "+t);
      System.out.println("Wolves left: "+wolves.getNext().count());
      System.out.println("Deer left: "+deer.getNext().count());
      
      // If we have an open file, write the counts to it
      if (output != null) {
        // Try it
        try{
          output.write(wolves.getNext().count()+"\t"+deer.getNext().count());
          output.newLine();
        } catch (Exception ex) {
          System.out.println("Couldn't write the data!");
          System.out.println(ex.getMessage());
          // Make output null so that we don't keep trying
          output = null;
        }
      }
    
      // Wait for one second
      //Thread.sleep(1000);
    }
    
    // If we have an open file, close it and null the variable
    if (output != null){
      try{
        output.close();}
      catch (Exception ex)
      {System.out.println("Something went wrong closing the file");}
      finally {
        // No matter what, mark the file as not-there
        output = null;}
    }
  }
}